JP6818121B2 - Internal combustion engine - Google Patents

Description

The present invention relates to an internal combustion engine including a crankcase having an oil pan at the bottom of a crank chamber accommodating a crank of a crankshaft and a transmission gear of a transmission, and an oil pump having a suction port in a storage area on the oil pan.

Patent Document 1 discloses a crankcase structure of an internal combustion engine. An oil pan is formed on the bottom of the crankcase. The oil pump sucks oil from the oil pan. Oil is supplied from the oil pump to the bearings of the crankshaft, the cylinder head, the main shaft of the transmission, and the counter shaft of the transmission via the oil cooler and the oil filter.

Japanese Unexamined Patent Publication No. 2014-196681

The oil is diffused as the crankshaft and transmission gear rotate. The oil warmed by the piston and cylinder and the relatively low temperature oil flowing through the mission gear are diffused and mixed by the crankshaft and mission gear, which hinders the warming of the internal combustion engine.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an internal combustion engine capable of realizing smoother warming than ever before.

According to the first aspect of the present invention, a crankcase having an oil pan at the bottom of a crank chamber accommodating a crank of a crankshaft and a transmission gear of a transmission, and a crankcase formed on the inner wall of the crank chamber in the direction of gravity from the crank. From the wall that at least partially separates the second oil path from the mission gear to the oil pan in the direction of gravity with respect to the first oil path to the oil pan, and from the second oil path on the oil pan. An oil pump having a suction port is provided in the separated storage area, and the oil is separated from the storage area by the wall on the oil pan and allows the inflow of oil through the gap formed in the wall in the stored oil. The auxiliary storage area is partitioned, and the crankcase includes a first case half body and a second case half body that is coupled to the first case half body at a mating surface, and the first case half body includes a first case half body. The gap is formed between the first rib that partitions the first flow path that is separated from the storage area and is opened at the mating surface and that arranges the suction port at a position away from the mating surface, and the mating surface. Then, a second rib forming a part of the wall is formed, and the second case half body is connected to the first flow path and the storage area at the mating surface. A third rib that partitions the flow path and a fourth rib that faces the second rib at the mating surface and forms a part of the wall are formed.

According to the second side surface, in addition to the configuration of the first side surface, the wall is the first wall extending from the oil pan of the crankcase toward the crankweb of the crankshaft and the wall from the upper wall of the crankcase. It has a second wall extending towards the crank web.

According to the third aspect, in addition to the configuration of the second aspect, the internal combustion engine includes a third wall that is connected to the upper end of the first wall and extends along the outer circumference of the crank web.

According to the first aspect, oil is diffused in the crank chamber as the crankshaft and transmission gear rotate. It prevents the high-temperature return oil warmed by the piston and cylinder and the relatively low-temperature return oil flowing through the mission gear from being diffused and mixed by the crankshaft and the mission gear, respectively. The oil warmed in this way is sucked into the oil pump from the suction port. The warmed oil circulates in the internal combustion engine. Smooth warming is achieved in an internal combustion engine.

In addition, warmed oil flows into the storage area during warm-up operation. Relatively cold oil flows into the auxiliary reservoir. When oil flows out from the suction port to the oil pump, the oil flows from the auxiliary storage area to the storage area through the gap. Warm oil is mixed with cold oil in a limited way. In this way, the oil can circulate along the second oil path. Lubrication of the mission gear is realized.

Furthermore, the oil in the storage area flows into the suction port from the second flow path of the second case half body through the first flow path of the first case half body. Since the relatively low temperature oil flows into the storage area through the gap on the half body side of the first case, the relatively low temperature oil is sufficient for the warm oil in the storage area prior to the inflow to the second flow path. Can be mixed. The decrease in the temperature of the oil flowing into the suction port is suppressed. Warming up of the internal combustion engine is promoted.

According to the second side surface, the space between the crank web and the oil pan is blocked by the first wall, and the space between the crank web and the upper wall of the crankcase is blocked by the second wall. It is suppressed that the low temperature oil on the transmission gear side enters the first oil path on the crankshaft side through the passage. Even if the crank web is partially exposed to the second oil path between the first wall and the second wall, the low temperature oil on the mission gear side will be released to the first oil path on the crankshaft side as the crank web rotates. Entry into is suppressed. Mixing of the oil thus warmed with the relatively cold oil is prevented. Warming up of the internal combustion engine is promoted.

According to the third aspect, the oil falling from the crank web is surely dropped along the third wall. The warmed oil is efficiently guided to the suction port. In this way, the warming up of the internal combustion engine can be promoted.

It is a side view which shows generally the whole image of the motorcycle which concerns on one Embodiment of this invention. It is an enlarged cross-sectional view along line 2-2 of FIG. It is an enlarged side view of the internal combustion engine which shows outline the outer surface of the 1st case half body of a crankcase. FIG. 3 is an enlarged partial plan view schematically showing the inner surface of the first case cover corresponding to FIG. FIG. 3 is an enlarged plan view schematically showing the inner surface of the first case half body corresponding to FIG. FIG. 3 is an enlarged plan view schematically showing the inner surface of the second case half body corresponding to FIG. It is an enlarged partial perspective view of the 1st case half body which shows the structure of the 1st flow path schematicly. It is an enlarged partial perspective view of the 2nd case half body which shows the structure of the 2nd flow path schematicly.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Here, the top, bottom, front, back, left, and right of the vehicle body shall be defined based on the viewpoint of the occupant who got on the motorcycle.

FIG. 1 schematically shows an overall configuration of a motorcycle according to an embodiment of the present invention. The motorcycle 11 includes a body frame 12. A front fork 14 is steerably supported by the head pipe 13 at the front end of the vehicle body frame 12. The front wheel WF is rotatably supported on the front fork 14 around the axle 15. A handlebar 16 is connected to the front fork 14 on the upper side of the head pipe 13. On the rear side of the vehicle body frame 12, the swing arm 18 is swingably supported on the pivot frame 17 around a support shaft 19 extending horizontally in the vehicle width direction. A rear wheel WR is rotatably supported around the axle 21 at the rear end of the swing arm 18.

An internal combustion engine 23 is mounted on the vehicle body frame 12 between the front wheel WF and the rear wheel WR. The internal combustion engine 23 includes a crankcase 24, a cylinder block 25 that is coupled to the crankcase 24 and has a cylinder axis that extends upward from the crankcase 24 and tilts forward, and a cylinder head 26 that is coupled to the cylinder block 25. A head cover 27 coupled to the cylinder head 26 is provided. The crankcase 24 supports a crankshaft (described later) that rotates around a rotation axis 28 extending parallel to the axle 21 of the rear wheel WR. The rotational movement of the crankshaft is transmitted to the rear wheel WR via a transmission device (not shown). The crankcase 24 is formed with two engine hangers 29 in the front and two in the rear. The engine hangers 29 are arranged one above the other in the front and rear respectively. The crankcase 24 is connected to and fixed to the vehicle body frame 12 by an engine hanger 29.

A fuel tank 31 is mounted on the vehicle body frame 12 above the internal combustion engine 23. A passenger seat 32 is mounted on the vehicle body frame 12 behind the fuel tank 31. Fuel is supplied from the fuel tank 31 to the fuel injection device of the internal combustion engine 23. When driving the motorcycle 11, the occupant straddles the occupant seat 32.

As shown in FIG. 2, a cylinder liner 33 is embedded in the cylinder block 25. The piston 34 is incorporated inside the cylinder liner 33. The cylinder liner 33 partitions the cylinder 35 that guides the axial movement of the piston 34. Here, the cylinder block 25 is formed with a single cylinder 35 that receives a single piston 34. A combustion chamber 36 is partitioned between the piston 34 and the cylinder head 26. A spark plug 37 facing the combustion chamber 36 is attached to the cylinder head 26.

The crankcase 24 is divided into a first case half body 24a and a second case half body 24b. The first case half body 24a and the second case half body 24b face each other on their inner surfaces. The first case half body 24a and the second case half body 24b are liquid-tightly coupled to each other at the mating surfaces to cooperately partition the crank chamber 39. The first case cover 41 is coupled to the outer surface of the first case half body 24a. The second case cover 42 is coupled to the outer surface of the second case half body 24b.

The crankshaft 43 is arranged between the journals 46a and 46b and the journals 46a and 46b connected to the ball bearings 44 and 45 fitted in the second case half body 24b and the first case half body 24a, respectively, and has a crank chamber. It includes a crank 47 housed in 39. The crank 47 has a crank web 48 integrated with the journals 46a and 46b, and a crank pin 49 connecting the crank web 48 to each other. The axes of the journals 46a and 46b coincide with the rotation axis 28. One end of a connecting rod 51 extending from the piston 34 is rotatably connected to the crank pin 49. The connecting rod 51 converts the axial movement of the piston 34 into the rotational movement of the crankshaft 43.

The crank pin 49 has an oil sump 52 extending along the axis of the crank pin 49 and a supply path 53 extending from the oil sump 52 in the radial direction of the crank pin 49 and opening in the contact area between the connecting rod 51 and the crank pin 49. And are partitioned. An oil passage 54 formed in the crankshaft 43 and extending from one end (right end) of the crankshaft 43 along the axial center of the crankshaft 43 is connected to the oil sump 52. The oil is introduced from one end of the crankshaft 43 and is supplied to the contact area between the connecting rod 51 and the crank pin 49.

An ACG (alternator) 55 is connected to one end of the crankshaft 43 that projects outward from the crankcase 24 in one direction. The ACG 55 includes a rotor 56 and a stator 57. The rotor 56 is connected to one end of the crankshaft 43 protruding from the crankcase 24 so as not to rotate relative to each other. The rotor 56 has a plurality of magnets 58 arranged in the circumferential direction. The rotor 56 surrounds the outer circumference of the stator 57. A plurality of coils 59 arranged in the circumferential direction are wound around the stator 57. The coil 59 follows an orbit facing the orbit of the magnet 58 when the rotor 56 rotates.

A dog clutch type transmission 61 is incorporated in the internal combustion engine 23. The transmission 61 is housed in the crankcase 24. The transmission 61 includes a main shaft 62 and a counter shaft 63 having an axis parallel to the axis of the crankshaft 43. The main shaft 62 and the counter shaft 63 are rotatably supported by the crankcase 24 by rolling bearings 64a, 64b, 65a, 65b.

A plurality of mission gears are supported on the main shaft 62 and the counter shaft 63. The transmission gear is arranged between the bearings and housed in the crank chamber 39. The transmission gears include a rotary gear 66a that is coaxially and relatively rotatably supported on the main shaft 62 or the counter shaft 63, and a fixed gear 66b that is fixed to the main shaft 62 so as not to rotate relative to each other and meshes with the corresponding rotary gear 66a. It includes a shift gear 66c that is supported by the main shaft 62 or the counter shaft 63 so as to be relatively non-rotatable and axially displaceable and meshes with the corresponding rotary gear 66a. Axial displacements of the rotary gear 66a and the fixed gear 66b are regulated. When the shift gear 66c is connected to the rotary gear 66a through axial displacement, the relative rotation between the rotary gear 66a and the main shaft 62 or the counter shaft 63 is regulated. When the shift gear 66c meshes with the rotary gear 66a of the other shaft, rotational power is transmitted between the main shaft 62 and the counter shaft 63. When the shift gear 66c is connected to the rotary gear 66a that meshes with the fixed gear 66b of the other shaft, the rotational power is transmitted between the main shaft 62 and the counter shaft 63. In this way, the specific transmission gear 66 meshes between the main shaft 62 and the counter shaft 63, so that the rotational power is transmitted from the main shaft 62 to the counter shaft 63 at a predetermined reduction ratio.

The main shaft 62 has an oil passage 67 extending along the axis of the main shaft 62 and a supply passage extending from the oil passage 67 in the radial direction of the main shaft 62 and opening in a contact area between the main shaft 62 and the rotary gear 66a. 68 is partitioned. An oil sump 69 partitioned between the inner surface of the second case half body 24b and the rolling bearing 64b is connected to the oil passage 67. The oil is introduced from the oil sump 69 into the oil passage 67 of the main shaft 62 and is supplied to the contact area between the main shaft 62 and the rotary gear 66a.

The main shaft 62 is connected to the crankshaft 43 through a primary reduction mechanism 71 housed between the crankcase 24 and the second case cover 42 on the outside of the crankcase 24. The primary reduction mechanism 71 includes a power transmission gear 72 and a driven gear 73 that is rotatably supported on the main shaft 62. The power transmission gear 72 is fixed to the other end of the crankshaft 43 projecting outward from the crankcase 24. The driven gear 73 meshes with the power transmission gear 72.

A friction clutch 74 accommodated between the crankcase 24 and the second case cover 42 is connected to the main shaft 62. The friction clutch 74 includes a clutch outer 74a and a clutch hub 74b. The driven gear 73 of the primary reduction mechanism 71 is connected to the clutch outer 74a. In the friction clutch 74, the connection and disconnection are switched between the clutch outer 74a and the clutch hub 74b according to the operation of the clutch lever.

A drive sprocket 75 of a transmission device arranged outside the crankcase 24 is coupled to the counter shaft 63. A drive chain 76 is wound around the drive sprocket 75. The drive chain 76 transmits the rotational power of the drive sprocket 75 to the rear wheel WR.

The counter shaft 63 has an oil passage 77 extending along the axis of the counter shaft 63 and a supply passage extending from the oil passage 77 in the radial direction of the counter shaft 63 and opening in a contact area between the counter shaft 63 and the rotary gear 66a. 78 is partitioned. An oil sump 79 partitioned between the inner surface of the first case half body 24a and the rolling bearing 65b is connected to the oil passage 77. The oil is introduced from the oil sump 79 into the oil passage 77 of the counter shaft 63 and supplied to the contact area between the counter shaft 63 and the rotary gear 66a.

An oil jet 81 is fixed to the first case half body 24a of the crankcase 24 below the cylinder liner 33. The oil jet 81 has a nozzle 81a that opens toward the piston 34. An oil sump 82 partitioned on the mating surfaces of the first case half body 24a and the first case cover 41 is connected to the oil jet 81. Oil is supplied from the nozzle 81a of the oil jet 81 to the piston 33.

As shown in FIG. 3, an oil pump 83 is installed on the outer surface of the first case half body 24a. The oil pump 83 is composed of, for example, a trochoid pump (registered trademark). The oil pump 83 includes an outer rotor 85 rotatably supported by the housing 84 on a cylindrical surface coaxial with an axis parallel to the rotation axis 28 of the crankshaft 43, and an outer rotor 85 arranged eccentrically with respect to the outer rotor 85. It includes an inner rotor 86 having an outer gear that meshes with the inner gear. The volume changes between the outer gear and the inner gear of the outer rotor 85 according to the rotation of the inner rotor 86, and the oil is sucked in and discharged according to the volume change.

An oil filter chamber 87 is partitioned below the oil pump 83 on the outer surface of the first case half body 24a. A suction path 88 connected to a suction port of the oil pump 83 is connected to the oil filter chamber 87. The suction passage 88 opens at the ceiling surface of the oil filter chamber 87. A suction port 89 penetrating from the inner surface to the outer surface of the first case half body 24a is partitioned along the bottom surface of the oil filter chamber 87. The oil filter chamber 87 is separated into a space on the suction path 88 side and a space on the suction port 89 side by the filter element 91. The oil is sucked from the suction port 89, filtered by the filter element 91, and then flows into the oil pump 83 from the suction passage 88.

As shown in FIG. 3, a connecting path 92 opens on the outer surface of the first case half body 24a. An oil passage 93 extending in the first case half body 24a from the discharge port of the oil pump 83 is connected to the connection passage 92. As shown in FIG. 4, the first case cover 41 is formed with a receiving port 94 that overlaps with the connecting path 92. An oil passage 96 extending in the first case cover 41 is connected to the receiving port 94 from the receiving port 94 to the connecting path 95 located above. The connecting path 95 is overlapped with the branch port 97 partitioned on the outer surface of the first case half body 24a. An oil passage 98 connected to the oil passage 54 of the crankshaft 43 is formed in the first case cover 41 adjacent to the connecting passage 95. The oil flows into the oil passage 98 of the first case cover 41 again from the connecting passage 95 via the branch port 97 of the first case half body 24a, and reaches the oil passage 54 of the crankshaft 43.

As shown in FIG. 3, an oil passage 99 extending toward the counter shaft 63 is partitioned in the first case half body 24a adjacent to the branch port 97. The oil passage 99 is connected to the oil sump 79 of the counter shaft 63 at the tip. The oil flows from the branch port 97 through the connecting path 95 of the first case cover 41 into the oil passage 99, and reaches the oil sump 79 of the counter shaft 63.

As shown in FIG. 5, the oil passage 99 leading to the bearing 65b of the counter shaft 63 is connected to the first crossing passage 102 on the inner surface of the first case half body 24a through the connection hole 101. As shown in FIG. 6, the first crossing road 102 is superposed on the second crossing road 103 partitioned by the second case half body 24b. The second crossing path 103 is connected to the oil passage 104 extending toward the oil sump 69 in the second case half body 24b. The oil flows from the first case half body 24a to the second case half body 24b via the first and second crossing passages 102 and 103, and reaches the oil sump 69 of the main shaft 62 from the oil passage 104.

The crankcase 24 has an oil pan 106 at the bottom. The oil pan 106 is filled with oil up to, for example, an oil level OL. On the inner wall of the crank chamber 39, at least a second oil path 108 from the mission gear 66 to the oil pan 106 in the gravity direction is provided at least partially with respect to the first oil path 107 from the crank 47 to the oil pan 106 in the gravity direction. A separating wall 109 is formed. The wall 109 includes a first wall 109a extending from the oil pan 106 of the crankcase 24 toward the outer periphery of the crankweb 48 of the crankshaft 43, and a second wall 109b extending from the upper wall of the crankcase 24 toward the crankweb 48. A third wall 109c extending forward from the upper end of the first wall 109a toward the first oil path 107 along the outer circumference of the crank web 48. Between the second wall 109b and the third wall 109c, the outer circumference of the crank web 48 faces the second oil path 108.

The first wall 109a partitions the main storage area 111 in the first oil path 107 below the oil level OL and the auxiliary storage area 112 in the second oil path 108 below the oil level OL. The auxiliary reservoir 112 is separated from the main reservoir 111 by a wall 109 on the oil pan 106. The suction port 89 is arranged on the oil pan 106 in the main storage area 111 separated from the second oil path 108.

The first case half body 24a has a first rib 114 for partitioning a first flow path 113 which is separated from the main storage area 111 and is opened at the mating surface and has a suction port 89 arranged at a position away from the mating surface ML. , As shown in FIG. 7, a gap 115 is formed between the mating surface ML and the second rib 116 forming a part of the first wall 109a. As shown in FIG. 8, the second case half body 24b has a third rib that partitions the second flow path 117 which is connected to the first flow path 113 by the mating surface ML and is connected to the main storage area 111. The 118 and the fourth rib 119 that faces the second rib 116 on the mating surface ML and forms a part of the first wall 109a are formed. In this way, the second rib 116 and the fourth rib 119 form the first wall 109a. The first wall 109a is partitioned with a gap 115 that allows oil to flow from the main storage area 111 to the auxiliary storage area 112 in the stored oil.

In the internal combustion engine 23, for example, the oil pan 106 is filled with oil up to the oil level OL. The oil to be stored is divided into a main storage area 111 on the first oil path 107 side and an auxiliary storage area 112 on the second oil path 108 side by a first wall 109a. However, the gap 115 of the first wall 109a allows oil to flow back and forth between the main storage area 111 and the auxiliary storage area 112.

When the internal combustion engine 23 starts, the oil pump 83 operates. The oil pump 83 sucks the oil stored in the oil pan 106 from the suction port 89. The oil discharged from the oil pump 83 is supplied to the cylinder 35, the crank pin 49, the main shaft 62, and the counter shaft 63. The oil warmed by the cylinder 35 is diffused in the crank chamber 39 according to the rotation of the crankshaft 43 and flows into the oil pan 106 via the first oil path 107. The oil flowing down from the main shaft 62 and the counter shaft 63 is diffused in the crank chamber 39 according to the rotation of the mission gear 66 and flows into the oil pan 106 via the second oil path 108. Oil is stored in the oil pan 106 up to the oil level OL.

The oil to be stored is divided into a main storage area 111 on the first oil path 107 side and an auxiliary storage area 112 on the second oil path 108 side by a first wall 109a. Therefore, the mixing of the oil diffused by the crankshaft 43 and the oil diffused by the transmission gear 66 is suppressed. The oil warmed in this way is sucked into the oil pump 83 from the suction port 89. The warmed oil circulates in the internal combustion engine 23. Smooth warming is realized in the internal combustion engine 23. When the oil in the main storage area 111 decreases, the oil in the auxiliary storage area 112 flows into the main storage area 111 through the gap 115 of the first wall 109a. The oil that has flowed in is warmed by the oil in the main storage area 111 and flows into the suction port 89.

In the present embodiment, the wall 109 extends from the oil pan 106 of the crankcase 24 toward the outer periphery of the crankweb 48 of the crankshaft 43, and from the upper wall of the crankcase 24 toward the crankweb 48. It has a second wall 109b. In this way, the space between the crank web 48 and the oil pan 106 is blocked by the first wall 109a, and the space between the crank web 48 and the upper wall of the crankcase 24 is blocked by the second wall 109b. It is suppressed that the relatively low temperature oil on the transmission gear 66 side enters the first oil path 107 on the crankshaft 43 side. Even if the crank web 48 is partially exposed to the second oil path 108 between the first wall 109a and the second wall 109b, the low temperature oil on the transmission gear 66 side is applied to the crankshaft in response to the rotation of the crank web 48. Entry into the first oil path 107 on the 43 side is suppressed. Mixing of the oil thus warmed with the relatively cold oil is prevented. The warming up of the internal combustion engine 23 is promoted.

The wall 109 is connected to the upper end of the first wall 109a and further has a third wall 109c extending forward along the outer circumference of the crank web 48 toward the first oil path 107 from the upper end of the first wall 109a. The oil falling from the crank web 48 surely falls to the first oil path 107 along the third wall 109c. The warmed oil is efficiently guided to the suction port 89. In this way, the warming up of the internal combustion engine 23 can be promoted.

As described above, in the internal combustion engine 23, the auxiliary storage area is separated from the main storage area 111 by the wall 109 on the oil pan 106 and allows the inflow of oil from the gap 115 formed in the wall 109 in the stored oil. 112 is partitioned. Warmed oil flows into the main storage area 111 during the warm-up operation. Relatively cold oil flows into the auxiliary reservoir 112. When the oil flows out from the suction port 89 to the oil pump 83, the oil flows from the auxiliary storage area 112 to the storage area 111 through the gap 115. Warm oil is mixed with cold oil in a limited way. In this way, the oil can circulate along the second oil path 108. Lubrication of the mission gear 66 is realized.

In forming the wall 109, the first case half body 24a of the crankcase 24 is opened by the mating surface ML separated from the main storage area 111, and the suction port 89 is arranged at a position away from the mating surface ML. A gap 115 is formed between the first rib 114 that partitions the flow path 113 and the mating surface ML, and the second rib 116 that forms a part of the wall 109 is formed. The second case half body 24b of the crankcase 24 is aligned with the third rib 118 that partitions the second flow path 117 that is connected to the first flow path 113 by the mating surface ML and is connected to the main storage area 111. A fourth rib 119 that faces the second rib 116 and forms a part of the wall 109 is formed on the surface ML. The oil in the main storage area 111 flows into the suction port 89 from the second flow path 117 of the second case half body 24b through the first flow path 113 of the first case half body 24a. Since the relatively low temperature oil flows into the main storage area 111 through the gap 115 on the side of the first case half body 24a, the relatively low temperature oil flows into the main storage area 111 prior to the inflow into the second flow path 117. In the region 111, it can be sufficiently mixed with warm oil. The decrease in the temperature of the oil flowing into the suction port 89 is suppressed. The warming up of the internal combustion engine 23 is promoted.

23 ... Internal combustion engine, 24 ... Crankcase, 24a ... First case half body, 24b ... Second case half body, 39 ... Crank chamber, 43 ... Crankshaft, 47 ... Crank, 48 ... Crank web, 61 ... Transmission, 66 ... mission gear, 83 ... oil pump, 89 ... suction port, 106 ... oil pan, 107 ... first oil path, 108 ... second oil path, 109 ... wall, 109a ... first wall, 109b ... second wall, 111 ... Storage area (main storage area), 112 ... Auxiliary storage area, 113 ... 1st flow path, 114 ... 1st rib, 116 ... 2nd rib, 117 ... 2nd flow path, 118 ... 3rd rib, 119 ... 4 ribs, ML ... mating surface.

Claims (3)

A crankcase (24) having an oil pan (106) at the bottom of a crank chamber (39) that houses the crank (47) of the crankshaft (43) and the transmission gear (66) of the transmission (61).
The direction of gravity from the mission gear (66) with respect to the first oil path (107) formed on the inner wall of the crank chamber (39) and reaching the oil pan (106) in the direction of gravity from the crank (47). A wall (109) that at least partially separates a second oil path (108) leading to the oil pan (106).
An oil pump (83) having a suction port (89) in a storage area (111) separated from the second oil path (108) on the oil pan (106) is provided.
The oil pan (106) is separated from the storage area (111) by the wall (109) and allows the inflow of oil through the gap (115) formed in the wall (109) in the stored oil. Auxiliary storage area (112) is partitioned and
The crankcase (24) includes a first case half body (24a) and a second case half body (24b) that is coupled to the first case half body (24a) at a mating surface (ML).
In the first case half body (24a), the suction port (89) is arranged at a position separated from the storage area (111) by a mating surface (ML) and separated from the mating surface (ML). The gap (115) is formed between the first rib (114) for partitioning the first flow path (113) and the mating surface (ML) to form a part of the wall (109). Two ribs (116) are formed,
The second case half body (24b) is provided with a second flow path (117) connected to the first flow path (113) and to the storage area (111) at the mating surface (ML). A third rib (118) to be partitioned and a fourth rib (119) forming a part of the wall (109) facing the second rib (116) on the mating surface (ML) are formed. An internal combustion engine characterized by. In the internal combustion engine according to claim 1, the wall (109) is
A first wall (109a) extending from the oil pan (106) of the crankcase (24) toward the crankweb (48) of the crankshaft (43).
An internal combustion engine having a second wall (109b) extending from an upper wall of the crankcase (24) toward the crank web (48). The internal combustion engine according to claim 2, further comprising a third wall (109c) connected to the upper end of the first wall (109a) and extending along the outer circumference of the crank web (48). organ.

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